Circuit interrupter



March 18, 1930. o. H. ESCHHOLZ CIRCUIT INTERRUPTER Filed Dec. 13.

ATTORNEY INVENTOR Ctto H. Eschholz BY M WITNESSES:

Patented Mar. 18, 1930 UNITED STATES @FFEQE OTTO H. ESCHHOLZ, OFWILKINSIBURG, PENNSYLVANIA, ASSIGNOR TO WESTINGHOUSE CIRCUIT INTERRUIPTER Application filed December 13, 1922. Serial No. 606,570.

My invention relates to electrical circuit interrupters, and moreparticularly to the type employing means for extinguishing an electricalare between the contact members.

An object of my invention is to provide a circuit interrupter or breakerin which the gases generated by an are between the contact members areemployed to extinguish the arc and to prevent its reformation after thecurrent wave has passed through zero.

Another object of my invention is to provide means for preventing thereformation or re-ignition of an electric are after the electric currenthas passed through the zero value by reducing the intensity of theelectrostatic field near the contact members.

Another object of my invention is to provide a circuit breaker withmeans for imparting, to an arc stream, a strong directional impulse in apredetermined path through the sudden release of confined gases.

A further object of my invention is to provide a shielding means for thecontact mem bers which also acts as a chamber for confining the gasesproduced by an electric are passing between the contact members.

To accomplish the above mentioned objects, I mount a shield near the endof each contact member. When the contact members 8 are closed, thesurfaces of these shieldsengage each other forming a chamber. The basesof the shields are resiliently connected to the contact members.

The creation of an are between the contact members results in thegeneration of gases, which cause the walls of the chamber to expandagainst their resilient supports. At the same time the movement of thecontact members tends to further separate the 9 surfaces of the shields.One portion of each shield piece is shorter than the remainder of theshield and the short sections of the'two complementary shields areplaced in registry. The efiect of the combined forces tending toseparate the shield surfaces is to cause the shorter sections toseparate with an explosive action in advance of the remaining sections.c

The contact members are provided with means for facilitating the arcterminal to travel to a point adjacent to the associated short sectionsof the shields. The escape of the arc gases is given a predetermineddirection, this movement being such that the escaping gases impart astrong directional impulse to the arc stream, tending to carry the arcstream away from the contact and thus prevent a re-establishment of theare after the current has reached zero value.

The shields are preferably of substantially spherical form as such ashape results in a more uniform potential gradient between the contactstructures upon separating contact members. A pointed electrode orshield produces an uneven potential gradient which facilitatesa'break-down of the intervening dielectric and the re-establishing ofthe are after the current has passed through zero value.

In the accompanying drawings:

Figure l is a plan view of a contact mem ber equipped with a shieldembodying my invention.

Fig. 2 is a cross sectional view of a contact giember and shield takenon line Hl[ll of ig. 1.

Fig. 3 is a view, similar to Fig. 2, of a con tact member equipped witha modified form of shield.

Similar reference numerals in the several views indicate like parts.

In the form of my invention shown in Figs. 1 and 2, a pair of relativelymovable contact members 1 and 2 are provided with similar arcing shields3 and 4, respectively. 'lfhese shields are of substantially ear shape,and are composed of a plurality of similar flexible sections 5 andseveral sections 6 and 7 of special shape which'are shorter than thesections 5. A broad band 8, secures the bases of the several sections toa strip of insulation 9 mounted on the contact member in such mannerthat the flexibility of the sections is not limited.

If desired, the insulation 9 may be omitted for a very low and uniformpotential gradient between the contact members.-

The outer ends of the several sections'extend beyond the adjacentcontact members, and define an opening 11 in each shield through whichthe contact members may project when in their closed position, as isshown in Fig. 2. During the operation of closing the contact members,the outer faces of the shields 3 and 4 meet in advance of the contactmembers and are deflected or crowded into a flattened position, butwithout the creation of openings in the walls of the shields.

A pair of arcing horns 12, 13 are mounted on contact members 1 and 2,respectively, adacent to the short sections 6 and 7 of the shields.

Upon the separation of the contact members, the electrical are 14,generated thereby, produces a quantity of arc gases which drives thewalls of the shields 3 and 4 outwardly with a tendency to separate them.

At the same time, the mechanical movement of the separating contacts 1and 2 also tends to separate the shields 3 and 4. Before actualseparation takes place, a high gaseous pressure is generated within theshields.

This is shown in Fig. 2, where the first separation of the shields istaking place between the short sections 6 and 7. The oreation of thisopening is accompanied by a rush of escaping gas.

Since the arc stream is directed close to this opening by the arcinghorns 12, 13, it

is caught up and swept along by the escapinggas. The path of the arcstream is thereby increased, and, as the, current value passes throughzero, arc re-establishment is prevented. In the meantime, the entiresurfaces of the shields 3 and 4 have separated.

. In the modification of my invention shown in Fig. 3, the shield 15 ismade to telescope within the shield 16. The surfaces of these shieldsare shortened, as at 17, in order to create an opening in advance of theseparati on of the main shield members. The princlples involved in theoperation of this modification of my invention are similar to thosedescribed in connection with the modification shown in Figs. 1 and 2.

It will thus be seen that I have invented a shield for relativelymovable contact members which utilizes the arc gases generated by theseparation of these members for imparting a predetermined blow-out forceto the arc stream.

It will be apparent that various modifications may be made in theapparatus without departing from the spirit of the invention, as definedin the accompanying claims.

I claim as my invention:

1. In an electrical circuit interrupter the combination with a contactmember for in terrupting a circuit, of a shield of resilient materialassociated therewith.

2. In an electrical circuit interrupter the combination with a contactmember, of a resilient shield having portions of different lengthsassociated therewith.

3. An electrical circuit interrupter comprising a plurality of contactmembers, a resilient shield for each of said contact members, saidshields forming a chamber upon the closing of said contact members.

4. An electrical circuit interrupter comprising a plurality of coactingcontact members, a resilient shield for each contact member, thesurfaces of the registering shields forming a chamber upon the closingof the contact members.

5. An electrical circuit interrupter comprising a plurality of contactmembers, a resilient shield for each contact member, the shields forminga chamber for confining the gases generated upon the occurrence of anare between the contact members.

6. An electrical circuit interrupter comprising contact members,cooperating shielding means for each of said contact members which, whenin a closed position, comprise a chamber for confining the gasesgenerated upon the occurrence of an arc between the contact members, andmeans for releasing said gases upon a predetermined separation of saidcontact members.

7. An electrical circuit interrupter comprising contact members,cooperating shielding means for each of said contact members which whenin a closed position comprise a chamber for confining the gasesgenerated upon the occurence of an are between the contact members, saidshielding means having a vent for releasing said gases opened upon apredetermined separation of said contact members.

8. In an electrical circuit interrupter the combination with contactmembers, of resilient shielding means for confining the gases generatedupon the separation of the contact members, said shielding means havinga vent operative upon a predetermined relative movement of the contactmembers for allowing the escape of said gases.

9. In a mechanism for extinguishing an electric arc, a plurality ofcontact members, cooperating shielding-means for each of said contactmembers, said shielding means being provided with a vent, said shieldingmeans operating to confine the gases generated upon the separation ofthe contact members until said vent is opened, said gases escapingthrough said vent.

10. In a circuit interrupting device a plurality of contact members,cooperating shielding means carried by each of said contact members,said shielding means forming a chamber about said contact members inadvance of the closing of said contact members, and said shielding meanspreserving the chamber for a time after the separatlon of said contactmembers.

11. A circuit interrupting device comprising a plurality of contactmembers, symmetrical shielding means surrounding said OTTO H. ESOHHOLZ.

